Illumination sources with decreasing wavelength may be utilized to meet demands for ever-shrinking features on semiconductor devices. However, decreasing the wavelength of illumination sources in lithography systems may increase the occurrence of defects that occur randomly or with a certain probability during fabrication, particularly in high-volume manufacturing in which exposure dose is minimized to increase throughput and decrease fabrication costs. Accordingly, the number and location of defects generated during a given fabrication run may vary. This increased likelihood of stochastic defects with short-wavelength illumination sources may be associated with a variety of factors including increased photon energy coupled with a reduced number of photons incident on a sample as well as stochastic variations in the absorption of these photons.
The presence of stochastic defects that manifest randomly (e.g. stochastic repeaters) provides increased challenges for defect detection as well as the generation of sample layouts and production recipes designed to mitigate the impact of these stochastic repeaters.